Propulsion has everything to do with swimming!! if it wasn't for propulsion you wouldn't move through the water. three elements of propulsion in swimming are:
Pull- the stroke pulls through the water and creates propulsion
Kick- the kick is another important element that creates propulsion
body position- although this doesn't create propulsion adjusting the body position in the stroke reduces drag and allows the propulsion created in the kick and pull of the stroke to propel the swimmer through the water.